Examining Field Measurements of Deep-Water Crest Statistics

This paper concerns the field measurements of wave crest elevations and wind speed obtained from fixed platforms in the North Sea during the period of 2011 to 2015. An improved quality control process is proposed by the authors aiming to maximise the amount of waves that are not discarded, whilst maintaining a reliable database. Applying this revised methodology, the total number of waves in the quality-controlled dataset is approximately 184 million. In total, the measurements correspond to 32 years of continuous data and contain approximately 0.0054% of rogue waves, according to the definition of Haver (2000) [1]. As the sea-state steepness increases, it is observed that the measured crest elevations are poorly modelled by the Forristall (2000) [2] distribution; similar behaviour is observed for sea-states with high wind speeds. The model by Tayfun and Fedele (2007) [3] is shown to be a better alternative in these cases, demonstrating that non-linear amplification beyond second-order cannot be neglected.